VICTORIA – Thousands of ballots for B.C.’s harmonized sales tax referendum were being stored in post offices after Canada Post locked out its urban employees across the country Wednesday.

Elections BC has prepared a contingency plan for post office disruptions, as officials try to get more than three million ballots delivered to homes across the province by June 24.

Federal Labour Minister Lisa Raitt told CTV Wednesday that since Canada Post moved from rotating strikes to a complete shutdown, the government will consider introducing back-to-work legislation. The strikes have cost Canada Post an estimated $1 million in lost revenue, and before the lockout management reduced urban mail delivery to three days a week.

Craig James, B.C.’s acting chief electoral officer at Elections BC, said Wednesday that no changes to the referendum timetable were being contemplated “at this time.” If the post office dispute drags into next week, Elections BC has the option to push back the deadline for returning completed ballots beyond the current date of July 22.

Elections BC officials said they will adjust their schedule if necessary to give voters the same amount of time to consider how they will vote.

Ballot packages went in the mail on Monday to regions outside Metro Vancouver and the Fraser Valley. They were scheduled to go out to those areas starting June 20.

Voters who receive their ballots can return them to one of 60 Service B.C. (formerly government agent) offices around the province instead of putting them in the mail.

Finance Minister Kevin Falcon urged people to vote “no” to the referendum question, which asks whether voters want to “extinguish” the HST and go back to the 12-per-cent federal and provincial sales tax.

Former premier and Fight HST organizer Bill Vander Zalm is running an advertising campaign urging people to vote yes, reminding people of the additional seven per cent tax extended to restaurant meals and a long list of services.

Faced with a strong public backlash against the HST, the B.C. and federal governments have committed to lower the rate to 11 per cent in 2012, and to 10 per cent in 2014.

Rebates of $175 for each child under 18 and each senior with an annual income less than $40,000 have been promised to cover extra costs until the rate can be lowered.